This invention relates to a novel process and in particular to a method for preparing 1-oxaspiro[2,5]-carbonitriles which can be used to make 4-substituted cyclohexanoic acids. The process, spinning disc reactor technology, also offers certain distinct advantages over traditional stirred tank reactors because of the reduced time of exposure of the carbonitrile to caustic which causes the carbonitrile to degrade to the amide.
The process, its intermediates and products described by this invention provides a means for making certain 4-substituted4-(3,4disubstitutedphenyl)cyclohexanoic acids which are useful for treating asthma, and other diseases which can be moderated by affecting the PDE IV enzyme and its subtypes. The reaction utilizes a phase transfer catalysed Darzen""s reaction. The products which can be made from the compound prepared herein are fully described in U.S. Pat. No. 5,552,483 issued Sep. 3, 1996. The information and representations disclosed therein, in so far as that information and those representations are necessary to the understanding of this invention and in its practice, are incorporated herein in total by reference.
This invention relates to a process for converting a substituted cyclohexan-1-one to a cis-(substituted)-1-oxobicyclo[2,5]octane-2-dicarbonitrile in the presence of base while minimizing the conversion of the 2 position nitrile to the amide comprising, in a spinning disc reactor (SDR):
i) preparing a first feed solution which comprises a 4-substituted cyclohexanone dissolved in an aqueous solvent
ii) preparing a second feed solution which comprises an aqueous solution of chloroacetonitrile, inorganic base and an organic ammonium halide;
iii) feeding together the first and second feed solutions in amounts which give molar ratios of ketone and inorganic base on the disc of between about 1:2.8 to 1:15.9;
iv) said disc is spinning at between about 500 and 4800 revolutions per minute, and
iv) having a residence time on the disc of between about 0.1 and 1 second.
In a second aspect, this invention relates to the compound 6Cyano-6-(3-cyclopentyloxy-4-methoxy-phenyl)-1-oxa-spiro[2.5]octane-2-carboxylic acid amide or a composition containing same.